1. Field of the Invention
The present invention relates to a packet data receiver, and more particularly, to a burst mode receiver for implementing a home networking system using telephone lines installed in a deck.
2. Description of the Related Art
Today's data networks use digital signal processing (DSP) devices, including modems, to transmit data through communications channels. In general, data is transmitted using an analog transmission signal described as a bit stream. These communications channels are appropriate for transmission of real-time information such as voice or video. Recently, packet-based information transmission using modems has been widely used.
Burst mode transmitters for transmitting packet-based information transmit a training sequence or a preamble before transmitting data so that a burst mode receiver receives a correct clock sample phase and a correct carrier phase for data recovery.
FIG. 1 is a schematic diagram showing the structure of a packet transmitted by a transmitter complying with a burst mode protocol. Referring to FIG. 1, the packet 10 can be transmitted by a transmission circuit installed in one or more modems. Each packet 10 comprises a preamble (P) 12, a header (H) 13, and payload data (D) 14.
The header 13 includes information items that identify the nature of the packet 10, for example, the version or type of the preamble, packet source or destination address, a data rate, error control parameter, and the packet length. These information items plays a role guaranteeing that information receiving systems correctly interpret the start of information transfer.
A burst mode receiver should sense the information items included in the header 13, and complete acquisition in a short preamble interval. Therefore, it is important for a burst mode receiver to have a good acquisition performance.
An essential technology which directly determines this performance of a burst mode receiver is a synchronization unit algorithm. However, only under a condition that stable frame synchronization is performed in a burst mode receiver using a preamble structure, the performance of the synchronization unit algorithm can be guaranteed.
Accordingly, in order to guarantee the stable performance of a burst mode receiver, frame synchronization for accurately detecting a burst arrival time is a prerequisite.